Differential amplification circuit wherein a DC level at an output terminal is automatically adjusted and a power amplifier wherein a BTL drive circuit is driven by a half wave
First Claim
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1. A differential amplification circuit wherein a DC level at an output terminal is automatically adjusted, said circuit comprising:
- a first differential amplifier comprising two input terminals, two output terminals, and a common input terminal for determining DC levels of said two output terminals for amplifying an AC signal input as a difference between said two input terminals and outputting to said two output terminals output signals of opposite polarity to each other;
a negative feedback circuit for applying negative feedback of mutually equal size between one of said two input terminals and one of said two output terminals and between the other of said two input terminals and the other of said two output terminals;
a nonlinear adder for substantially adding two output signals generated at said two output terminals and clamping a change in the result of the addition to a predetermined value or less; and
a second differential amplifier for applying a comparison output signal responsive to a difference between an output signal of said nonlinear adder and a reference voltage of a reference power supply to said common input terminal of said first differential amplifier.
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Abstract
A power amplifier with highly efficient power consumption with fewer switching power supplies. The power amplifier comprises a first differential amplifier having two input terminals and a common terminal, a BTL amplifier consisting of a first SEPP OCL and a second SEPP OCL, a nonlinear adder, an adder, a second differential amplifier, and a switching power supply.
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Citations
8 Claims
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1. A differential amplification circuit wherein a DC level at an output terminal is automatically adjusted, said circuit comprising:
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a first differential amplifier comprising two input terminals, two output terminals, and a common input terminal for determining DC levels of said two output terminals for amplifying an AC signal input as a difference between said two input terminals and outputting to said two output terminals output signals of opposite polarity to each other; a negative feedback circuit for applying negative feedback of mutually equal size between one of said two input terminals and one of said two output terminals and between the other of said two input terminals and the other of said two output terminals; a nonlinear adder for substantially adding two output signals generated at said two output terminals and clamping a change in the result of the addition to a predetermined value or less; and a second differential amplifier for applying a comparison output signal responsive to a difference between an output signal of said nonlinear adder and a reference voltage of a reference power supply to said common input terminal of said first differential amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification